Context: A friend (“Mr M”) asked about how to practice self-enquiry. Below are his questions (lightly edited), my replies (tidied), the full text of Bassui’s letter (unaltered), two potent koans from John Tan, and links for further reading.

Mr M wrote:

I’ve been doing inquiry in two ways: (1) active — staying present during activities (e.g., doing the dishes), silently asking “Who am I?” and then resting in that; and (2) seated — sitting to inquire “Who am I?” and resting in that. I usually find I’m resting in a kind of space in my head behind everything, being aware of the body and also trying to be aware of being aware, which simply feels like nothingness.
I haven’t had time to read what you sent today before replying here. I asked because teachers like Rupert say to remain in Being as much as possible until it’s continuous, and ATR recommends at least an hour of sitting per day, saying people who don’t sit are usually full of it (paraphrasing). However, I couldn’t find your specific recommendation beyond that article.

Soh replied:

• “Who am I” is not a verbal activity. It’s to discover what you are before all thoughts and words.
• Read: Self Enquiry, Neti Neti and the Process of Elimination
• Also: Tips on Self-Enquiry (Investigate “Who Am I”)
• You are not space. Space too, is an object of perception. Neti neti (not this, not that). What is aware of it? If you’re “resting in space,” inquire further — what are you, precisely?
• Practice recommendation: Make inquiry your dedicated practice. Do it as much as possible throughout the day, and also set aside quality sitting time (upright posture, e.g., lotus) for focused inquiry.

Please read: 

BASSUI’S LETTER TO LORD NAKAMURA — GOVERNOR OF AKI PROVINCE (full text, unchanged)

You ask me how to practice Zen with reference to this phrase from a sutra: "Mind, having no fixed abode, should flow forth." There is no express method for attaining enlightenment. If you but look into your Self-nature directly, not allowing yourself to be deflected, the Mind flower will come into bloom. Hence the sutra says: "Mind, having no fixed abode, should flow forth." Thousands of words spoken directly by Buddhas and Patriarchs add up to this one phrase. Mind is the True-nature of things, transcending all forms. The True-nature is the Way. The Way is Buddha. Buddha is Mind. Mind is not within or without or in between. It is not being or nothingness or non-being or non-nothingness or Buddha or mind or matter. So it is called the abodeless Mind. This Mind sees colors with the eyes, hears sounds with the ears. Look for this master directly!

A Zen master [Rinzai] of old says: "One's body, composed of the four primal elements can't hear or understand this preaching. The spleen or stomach or liver or gall bladder can't hear or understand this preaching. Empty-space can't understand it. Then what does hear and understand?" Strive to perceive directly. If your mind remains attached to any form or feeling whatsoever, or is affected by logical reasoning or conceptual thinking, you are as far from true realization as heaven is from earth.

How can you cut off at a stroke the sufferings of birth-and-death? As soon as you consider how to advance, you get lost in reasoning; but if you quit you are adverse to the highest path. To be able neither to advance nor to quit is to be a "breathing corpse." If in spite of this dilemma you empty your mind of all thoughts and push on with your zazen, you are bound to enlighten yourself and apprehend the phrase "Mind, having no fixed abode, should flow forth." Instantly you will grasp the sense of all Zen dialogue a well the profound and subtle meaning of the countless sutras.

The layman Ho asked Baso: "What is it that transcends everything in the universe?" Baso answered: ' I will tell you after you have drunk up the waters of the West River in one gulp.' Ho instantly became deeply enlightened. See here, what does this mean? Does it explain the phrase "Mind, having no fixed abode, should flow forth," or does it point to the very one reading this? If you still don't comprehend, go back to questioning, "What is hearing now?" Find out this very moment! The problem of birth-and-death is momentous, and the world moves fast. Make the most of time, for it waits for no one.

Your own Mind is intrinsically Buddha. Buddhas are those who have realized this. Those who haven't are the so-called ordinary sentiant beings. Sleeping and working, standing and sitting, ask yourself "What is my own Mind?" looking into the source from which your thoughts arise. What is this subject that right now perceives, thinks, moves, works, goes forth, or returns? To know it you must intensely absorb yourself in the question. But even though you do not realize it in this life, beyond a doubt you will in the next because of your present efforts.

In your zazen think in terms of neither good nor evil. Don't try to stop thoughts from arising, only ask yourself; 'What is my own Mind?" Now, even when your questioning goes deeper and deeper you will get no answer until finally you will reach a cul-de-sac, your thinking totally checked. You won't find anything within that can be called "I" or "Mind." But who is it that understands all this? Continue to probe more deeply yet and the mind that perceives there is nothing will vanish; you will no longer be aware of questioning but only of emptiness. When awareness of even emptiness disappears, you will realise there is no Buddha outside Mind and no Mind outside Buddha. Now for the first time you will discover that when you do not hear with your ears you are truly hearing, and when you do not see with your eyes you are really seeing Buddhas of the past, present, and future. But don't cling to any of this, just experience it for yourself!

See here, what is your own Mind? Everyone's Original-nature is not less than Buddha. But since men doubt this and search for Buddha and Truth outside their Mind, they fail to attain enlightenment, being helplessly driven within cycles of birth-and-death, entangled in karma both good and bad. The source of all karma bondage is delusion i.e. the thoughts, feelings, and perceptions (stemming from ignorance). Rid yourself of them and you are emancipated. Just as ash covering a charcoal fire is dispersed when the fire is fanned, so these delusions vanish once you realize your Self-nature.

During zazen neither loathe nor be charmed by any of your thoughts. With your mind turned inward, look steadily into their source and the delusive feelings and perceptions in which they are rooted will evaporate. This is not yet Self realization, however, even though your mind becomes bright and empty like the sky, you have awareness of neither inner nor outer, and all the ten quarters seem clear and luminous. To take this for realization is to mistake a mirage for reality. Now even more intensely search this mind of yours which hears. Your physical body, composed of the four basic elements, is like a phantom, without reality, yet apart from this body there is no mind. The empty-space of ten quarters can neither see nor hear; still, something within you does hear and distinguish sounds,

Who or what is it?

When this question totally ignites you, distinctions of good and evil, awareness of being or emptiness, vanish like a light extinguished on a dark night. Though you are no longer consciously aware of yourself, still you can hear and know you exist. Try as you will to discover the subject hearing, your efforts will fail and you will find yourself at an impasse. All at once your mind will burst into great enlightenment and you will feel as though you have risen from the dead, laughing loudly and clapping your hands in delight. Now for the first time you will know that Mind itself is Buddha.

Were someone to ask, "What does one's Buddha-mind look like?' I would answer: "In the tree fish play, in the deep sea bird are flying." What does this mean? If you don't understand it, look into your own Mind and ask yourself: "What is he, this master who sees and hears?"

Make the most of time: it waits for no one!

- The Three Pillars of Zen

Also: What is your very Mind right now?

"John Tan sent two potent koans to a friend -- good for contemplation.

1. Without thoughts, tell me what is your very mind right now?

2. Without using any words or language, how do you experience ‘I’ right now?

(In the Zen tradition, we also have, "When you're not thinking of anything good and anything bad, at that moment, what is your original face?" (Sixth Patriarch Hui-Neng), "What is the original face before your parents were born?"

A similar koan led to my initial sudden awakening in February 2010.)

Someone replied, “No mind"

That friend of ours told John Tan something similar and got 'smacked'.

John Tan: Without any thought, tell me what is your very mind now?

Friend: Void. Hollow.

John Tan: Smack your head... lol.

John Tan: Without using any words or language, how do you experience 'I' right now'?

Friend: ....something about personality, habits, opinions...

John Tan: If there is no thoughts, how can there be habits, opinions and personality? Everywhere you go, how can you miss it? Day in and day out, wherever and whenever there is, there 'you' are! How can 'you' distant yourself from 'yourself'?"

More by John Tan:

"Mahamudra, Dzogchen, Zen, whatever tradition, how are they able to deny you from yourself? So who are You?"

Self-Enquiry is called a direct path for a reason:

“Don’t relate, don’t infer, don’t think. Authenticating ‘You’ yourself requires nothing of that. Not from teachers, books, Mahamudra, Dzogchen, Zen or even Buddha, whatever comes from outside is knowledge. What that comes from the innermost depth of your own beingness, is the wisdom of you yourself.

There is no need to look for any answers. Ultimately, it is your own essence and nature. To leap from the inferencing, deducting and relating mind into the most direct and immediate authentication, the mind must cease completely and right back into the place before any formation of artificialities. If this ‘eye’ of immediacy isn’t open, everything is merely knowledge and opening this eye of direct perception is the beginning of the path that is pathless. Ok enough of chats and there have been too much words. Don’t sway and walk on. Happy journey!’

Mr. R, I have been very direct to you and it is just a simple question of what is your mind right now and nothing else. There is no other path more straightforward than that.

I have told you to put aside, all thoughts, all teachings, even Dzogchen, Mahamudra, Zen and just [asked] ‘what is your mind right now?’. Isn’t that telling you straight to the point, not wasting time and words? I have also told you whatever comes from external is knowledge, put all those aside. Wisdom comes from within yourself directly. But you have cut and pasted me all the texts, conversations, Zen, Mahamudra, Dzogchen, Madhyamaka that I have told you to put aside.

You asked me what is my advice. Still the same. Don’t go after experiences and knowledge, you have read and known enough, so return back to simplicity. Your duty is not to know more, but to eliminate all these and [get] back to the simplicity of the direct taste. Otherwise you will have to waste a few more years or decades to return back to what that is most simple, basic and direct.

And from this simplicity and directness, you then allow your nature to reveal the breadth and depth through constantly authenticating it in all moments and all states through engagement in different conditions.

So unless you drop everything and [get] back into a clean, pure, basic simplicity, there is no real progress in practice. Until you understand the treasure of simplicity and start back from there, every step forward is a retrogress.“

– John Tan, 2020"

Soh replied (practice pointers):

• Neti neti. If it’s “nothingness,” that’s still an experience/idea. Before finding your Self, you have to reject all objects of consciousness as not what you are, not your true Self — neti-neti. Otherwise you keep mistaking ever-subtler phenomena for your identity and veil the Self, which is pure Beingness and Consciousness. Only by refusing these identifications can the Self stand revealed.
• Realization is not “nothing.” When the Self is realized, it’s a certainty of Being.
• Make inquiry your dedicated practice. Do it throughout the day, and also set aside proper sitting. Upright posture (e.g., lotus) helps prevent sleepiness.
• Whatever appears (lights, energy, fear, vacuums) — totally fine as objects of consciousness, but keep asking: “What is conscious or aware?” What is that Source of that light of consciousness that illuminates everything? Who or What am I? Keep inquiring.

Short video: YouTube Short

Further reading

• Bassui’s letters are collected in Philip Kapleau’s The Three Pillars of Zen (see the “Letters” section, incl. “To Lord Nakamura…”).
• The phrase “mind having no fixed abode” echoes the Diamond Sūtra’s teaching on the non-abiding mind.
• Brief bio of Bassui Tokushō (Rinzai Zen master).